Moriyuki Hamada

Luteimicrobium album sp. nov., a novel actinobacterium isolated from a lichen collected in Japan, and emended description of the genus Luteimicrobium

A novel Gram-stain-positive actinobacterium, designated RI148-Li105T, was isolated from a lichen sample from Rishiri Island, Japan, and its taxonomic position was investigated by a polyphasic approach. 16S rRNA gene sequencing study indicated that strain RI148-Li105T was related to the type strain of Luteimicrobium subarcticum, with a similarity of 97.8%. Cells of strain RI148-Li105T exhibited a rod–coccus cycle. The diagnostic cell-wall diamino acid of this organism was lysine and the peptidoglycan type was found to be A4α. The predominant menaquinones were MK-8(H2) and MK-9(H2), and the major fatty acids were iso-C16:0, C17:1 ω9c and C17:0. The DNA G+C content was 73.6 mol%. The major phenotypic characteristics of strain RI148-Li105T basically corresponded to those of the genus Luteimicrobium excluding the fatty acid composition. These results suggest that strain RI148-Li105T should be affiliated with the genus Luteimicrobium. Meanwhile, DNA–DNA hybridization and some phenotypic characteristics revealed that the strain differs from L. subarcticum. Therefore, strain RI148-Li105T represents a novel species of the genus Luteimicrobium, for which the name Luteimicrobium album sp. nov. is proposed. The type strain of Luteimicrobium album is RI148-Li105T (=NBRC 106348T=DSM 24866T).

Thioprofundum hispidum sp. nov., an obligately chemolithoautotrophic sulfur-oxidizing gammaproteobacterium isolated from the hydrothermal field on Suiyo Seamount, and proposal of Thioalkalispiraceae fam. nov. in the order Chromatiales

A novel mesophilic, facultatively anaerobic, sulfur-oxidizing bacterial strain, designated gps61(T), was isolated from a surface rock sample collected from the hydrothermal field of Suiyo Seamount on the Izu-Bonin Arc in the Western Pacific Ocean. Cells of the isolate were rod-shaped with a single sheathed polar flagellum. Neither extensive internal membranes nor storage materials were present in the cells. In a 20 % CO(2) atmosphere, strain gps61(T) grew using thiosulfate, sulfur or tetrathionate as electron donors and oxygen or nitrate as electron acceptors. Other substrates, including organic acids and sugars, did not support growth, indicating that strain gps61(T) was an obligate chemolithoautotroph. 16S rRNA gene sequence analysis revealed that strain gps61(T) was closely related to Thioprofundum lithotrophicum 106(T) (98.5 % sequence similarity) in the order Chromatiales. Phylogenetic trees grouped strain gps61(T) and Thioprofundum lithotrophicum in the same cluster along with Thioalkalispira microaerophila and Thiohalophilus thiocyanoxidans, but it was apparent from the analysis that the novel strain had definitely departed from the family lineage. On the basis of its phylogenetic position along with its morphological and physiological characteristics, strain gps61(T) ( = NBRC 101261(T)  = DSM 18546(T)) represents a novel species of the genus Thioprofundum, for which the name Thioprofundum hispidum sp. nov. is proposed. In addition, we propose a novel family name, Thioalkalispiraceae, in the order Chromatiales, to accommodate the genera Thioalkalispira, Thiohalophilus and Thioprofundum.

A genome sequence-based approach to taxonomy of the genus Nocardia.

The genus Nocardia includes both pathogens and producers of useful secondary metabolites. Although 16S rRNA analysis is required to accurately discriminate among phylogenetic relationships of the Nocardia species, most branches of 16S rRNA-based phylogenetic trees are not reliable. In this study, we performed in silico analyses of the genome sequences of Nocardia species in order to understand their diversity and classification for their identification and applications. Draft genome sequences of 26 Nocardia strains were determined. Phylogenetic trees were prepared on the basis of multilocus sequence analysis of the concatenated sequences of 12 genes (atpD-dnaJ-groL1-groL2-gyrB-recA-rpoA-secA-secY-sodA-trpB-ychF) and a bidirectional best hit. To elucidate the evolutionary relationships of these genes, the genome-to-genome distance was investigated on the basis of the average nucleotide identity, DNA maximal unique matches index, and genome-to-genome distance calculator. The topologies of all phylogenetic trees were found to be essentially similar to each other. Furthermore, whole genome-derived and multiple gene-derived relationships were found to be suitable for extensive intra-genus assessment of the genus Nocardia.

Actinomycetospora iriomotensis sp. nov., a novel actinomycete isolated from a lichen sample

An actinomycete strain, IR73-Li102T, was isolated from a lichen sample obtained from Iriomote Island, Japan, and subsequently characterized using a polyphasic approach. Comparative 16S rRNA gene sequence analysis revealed that strain IR73-Li102T had the highest sequence similarities with Actinomycetospora chiangmaiensis YIM 0006T (98.3%), A. corticola 014-5T (98.1%) and A. rishiriensis RI109-Li102T (98.0%). However, DNA–DNA hybridization assays, as well as physiological and biochemical analyzes, showed that strain IR73-Li102T could be clearly differentiated from its closest phylogenetic relatives. The strain contained meso-diaminopimelic acid, and arabinose and galactose were present in whole-cell hydrolysates. The predominant menaquinone was MK-8(H4), and the diagnostic phospholipids were phosphatidylethanolamine, phosphatidylcholine, phosphatidylinositol and diphosphatidylglycerol. The major cellular fatty acid was iso-C16:0 (58%). The chemotaxonomic properties of strain IR73-Li102T were consistent with those shared by members of the genus Actinomycetospora. On the basis of the phenotypic features and DNA–DNA hybridization data, strain IR73-Li102T (= NBRC 106365T = KCTC 19783T) represents a novel species of the genus Actinomycetospora, for which the name Actinomycetospora iriomotensis sp. nov. is proposed.

Reclassification of Leifsonia ginsengi (Qiu et al. 2007) as Herbiconiux ginsengi gen. nov., comb. nov. and description of Herbiconiux solani sp. nov., an actinobacterium associated with the phyllosphere of Solanum tuberosum L.

In the context of studying the effects of transgenic fructan-producing potatoes on the community structure of phyllosphere bacteria, a group of strains closely related to the species Leifsonia ginsengi was isolated. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the new isolates and L. ginsengi DSM 19088(T) formed a lineage at the genus level and this finding was supported by chemotaxonomic characterization. The peptidoglycan type of the representative isolate, K134/01(T), and L. ginsengi DSM 19088(T) was B2γ, with d- and l-diaminobutyric acid as the diagnostic diamino acid and glycine, alanine and threo-3-hydroxyglutamic acid. The almost-complete substitution of glutamic acid by threo-3-hydroxyglutamic acid supported the differentiation of the new strains from recognized species of the genus Leifsonia. Furthermore, the detection of substantial amounts of the fatty acid cyclohexyl-C(17 : 0) in the new isolates and L. ginsengi DSM 19088(T) was a prominent chemotaxonomic feature for a clear demarcation of these strains from all genera of the family Microbacteriaceae that display the B2γ cell-wall type. Comparative phylogenetic and phenotypic analyses of the isolates and L. ginsengi DSM 19088(T) revealed the separate species status of the isolates. On the basis of these results, it is proposed that L. ginsengi should be classified as the type species of a novel genus, Herbiconiux gen. nov., with the name Herbiconiux ginsengi gen. nov., comb. nov. (type strain wged11(T) = CGMCC 4.3491(T) = JCM 13908(T) = DSM 19088(T) = NBRC 104580(T)). The phyllosphere isolates are assigned to a novel species, Herbiconiux solani sp. nov. (type strain K134/01(T) = DSM 19813(T) = LMG 24387(T) = NBRC 106740(T)).

Leucobacter denitrificans sp. nov., isolated from cow dung

The bacterial strain M1T8B10T was isolated from cow dung in Suwon, Republic of Korea. The strain was a Gram stain-positive rod, nonmotile, and non-spore-forming. According to 16S rRNA gene sequence analysis, the strain fell within the clade of the genus Leucobacter, showing the highest sequence similarities with Leucobacter aridicollis L-9T (98.7%), Leucobacter iarius 40T (98.4%), and Leucobacter komagatae JCM 9414T (98.2%). Cell-wall peptidoglycan contained the diagnostic diamino acid 2,4-diaminobutyric acid of the genus Leucobacter, showing B-type cross-linked peptidoglycans. The major fatty acids were anteiso-C15:0, iso-C16:0, and anteiso-C17:0. The quinone system consisted of the menaquinones MK-11 (78%) and MK-10 (22%). The polar lipid profiles contained diphosphatidylglycerol, phosphatidylglycerol, and an unidentified glycolipid. Differences in several physiological features including nitrate reduction enabled the isolate to be differentiated from all recognized Leucobacter species. Based on these phylogenetic, chemotaxonomic, and phenotypic results, the isolate represents a novel species, for which the name Leucobacter denitrificans sp. nov. is proposed. The type strain is M1T8B10T (=KACC 14055T =NBRC 106309T).

Lysinimonas soli gen. nov., sp. nov., isolated from soil, and reclassification of Leifsonia kribbensis Dastager et al. 2009 as Lysinimonas kribbensis sp. nov., comb. nov.

A Gram-stain-positive, non-motile rod, designated strain SGM3-12(T), was isolated from paddy soil in Suwon, Republic of Korea. 16S rRNA gene sequence analysis revealed that the strain represented a novel member of the family Microbacteriaceae. The nearest phylogenetic neighbour was Leifsonia kribbensis MSL-13(T) (97.4 % 16S rRNA gene sequence similarity). Strain SGM3-12(T) and Leifsonia kribbensis MSL-13(T) formed a distinct cluster within the family Microbacteriaceae. Strain SGM3-12(T) contained MK-12(H2) and MK-11(H2) as the predominant menaquinones with moderate amounts of MK-12 and MK-11; anteiso-C15 : 0 and iso-C16 : 0 as the major cellular fatty acids (>10 % of total); and diphosphatidylglycerol, phosphatidylglycerol and unidentified glycolipids as the polar lipids. The peptidoglycan type of the isolate was B1δ with L-Lys as the diagnostic cell-wall diamino acid. On the basis of these results, strain SGM3-12(T) represents a novel species within a new genus, for which the name Lysinimonas soli gen. nov., sp. nov. is proposed (the type strain of the type species is SGM3-12(T) = KACC 13362(T) = NBRC 107106(T)). It is also proposed that Leifsonia kribbensis be transferred to this genus as Lysinimonas kribbensis comb. nov. (the type strain is MSL-13(T) = DSM 19272(T) = JCM 16015(T) = KACC 21108(T) = KCTC 19267(T)).

Homoserinimonas aerilata gen. nov., sp. nov., a novel member of the family Microbacteriaceae isolated from an air sample in Korea

A bacterial strain isolated from an air sample, strain 5317J-19T, was characterized. The isolate was an aerobic, motile, Gram-positive rod. The organism was able to grow between 4 and 35°C and between pH 6 and 9. The predominant fatty acids were anteiso-C15:0 and iso-C16:0. The major respiratory menaquinones were MK-12 and MK-11, and the minor ones were MK13, MK-10, and MK-9. Genomic DNA G+C content was 66 mol%. The diagnostic diamino acid of the peptidoglycan is presumably D-Orn. The peptidoglycan is supposed to be B2β type. The 16S rRNA gene sequence analysis indicated that this isolate belongs to the family Microbacteriaceae and had the highest sequence similarities with Salinibacterium xinjiangense 0543T (97.6%), Salinibacterium amurskyense KMM 3673T (97.2%), and Leifsonia bigeumensis MSL-27T (97.2%). Phylogenetic analysis and phenotypic characteristics support the proposal of a new genus and a novel species, with the name Homoserinimonas aerilata gen. nov., sp. nov. The type strain of Homoserinimonas aerilata is 5317J-19T (=KACC 15522T =NBRC 108729T).A bacterial strain isolated from an air sample, strain 5317J-19T, was characterized. The isolate was an aerobic, motile, Gram-positive rod. The organism was able to grow between 4 and 35°C and between pH 6 and 9. The predominant fatty acids were anteiso-C15:0 and iso-C16:0. The major respiratory menaquinones were MK-12 and MK-11, and the minor ones were MK13, MK-10, and MK-9. Genomic DNA G+C content was 66 mol%. The diagnostic diamino acid of the peptidoglycan is presumably D-Orn. The peptidoglycan is supposed to be B2β type. The 16S rRNA gene sequence analysis indicated that this isolate belongs to the family Microbacteriaceae and had the highest sequence similarities with Salinibacterium xinjiangense 0543T (97.6%), Salinibacteriumamurskyense KMM 3673T (97.2%), and Leifsonia bigeumensis MSL-27T (97.2%). Phylogenetic analysis and phenotypic characteristics support the proposal of a new genus and a novel species, with the name Homoserinimonas aerilata gen. nov., sp. nov. The type strain of Homoserinimonas aerilata is 5317J-19T (=KACC 15522T =NBRC 108729T).

Actinomycetospora rishiriensis sp. nov., isolated from a lichen.

An actinomycete, strain RI109-Li102(T), was isolated from a lichen sample obtained from Rishiri Island in Japan. Cells of strain RI109-Li102(T) were Gram-positive, aerobic and non-motile and formed bud-like spore chains. The isolate grew with 0-3 % (w/v) NaCl, at pH 5-9 and at 10-30 °C (optimum 30 °C). The whole-cell hydrolysate contained meso-diaminopimelic acid, arabinose and galactose. The predominant menaquinone was MK-8(H(4)) and the diagnostic phospholipids were phosphatidylethanolamine, phosphatidylcholine, phosphatidylinositol and diphosphatidylglycerol. The major cellular fatty acids were iso-C(16 : 0) and iso-C(16 : 1) H. Comparative 16S rRNA gene sequence analysis revealed that strain RI109-Li102(T) was most closely related to Actinomycetospora corticicola 014-5(T) (99.0 % rRNA gene sequence similarity) and Actinomycetospora chiangmaiensis YIM 0006(T) (98.4 %). However, DNA-DNA hybridization assays, as well as physiological and biochemical analyses, showed that strain RI109-Li102(T) could be differentiated from its closest phylogenetic relatives. It is proposed that strain RI109-Li102(T) ( = NBRC 106356(T) = KCTC 19782(T)) be classified as the type strain of a novel species, with the name Actinomycetospora rishiriensis sp. nov.

Streptomyces hokutonensis sp. nov., a novel actinomycete isolated from the strawberry root rhizosphere.

A polyphasic approach was used to determine the taxonomic position of actinomycete strain R1-NS-10T, which was isolated from a sample of strawberry root rhizosphere obtained from Hokuto, Yamanashi, Japan. Strain R1-NS-10T was Gram-staining-positive and aerobic, and formed brownish-white aerial mycelia and grayish-brown substrate mycelia on ISP-2 medium. The strain grew in the presence of 0–5% (w/v) NaCl and optimally grew without NaCl. The strain grew at pH 5–8, and the optimum for growth was pH 7. The optimal growth temperature was 30 °C, but the strain grew at 5–37 °C. Whole-cell hydrolysates of strain R1-NS-10T contained A2pm, galactose, mannose and rhamnose. The predominant menaquinones were MK-9(H6) and MK-9(H8). The major cellular fatty acids were anteiso-C15:0 and iso-C16:0. Comparative 16S rRNA gene sequence analysis revealed that strain R1-NS-10T was most closely related to Streptomyces prunicolor NBRC 13075T (99.4%). The draft genome sequences of both strains were determined for characterization of genome sequence-related parameters such as average nucleotide identity (ANI) and the diversity of secondary metabolite biosynthetic gene clusters. DNA–DNA hybridization (DDH) and ANI values for both strains were below the species delineation cutoff, and differences in physiological and biochemical characteristics differentiated strain R1-NS-10T from its closest phylogenetic relative. On the basis of these data, we propose that strain R1-NS-10T (=NBRC 108812T=KCTC 29186T) should be classified as the type strain of a novel Streptomyces species named Streptomyces hokutonensis sp. nov.